<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			var test = function(){
				console.log("已经监听到click事件，回调函数被执行。")
			}
		</script>
	</head>
	<body>
		<button id="btn">按钮</button>
		<script>
			var btn = document.getElementById("btn");
			btn.addEventListener("click",test,true);
		</script>
		
		<button onclick="del()">移除监听器</button>
		<script>
			function del(){
				var btn = document.getElementById("btn");
				btn.removeEventListener("click",test,true);
				console.log("按钮的监听事件已经被删除")
			}
		</script>
	</body>
</html>
